// ECMAScript 2016

// Array.prototype.includes ------------------------------------
// ES2015中的includes 是字符串的  ES2016中的includes是数组的
const arr = ['foo', 1, NaN, false]

console.log(arr.indexOf('foo'));    //0
console.log(arr.indexOf('bar'));    //-1
console.log(arr.indexOf(NaN));      //-1
// 补充的数组includes
console.log(arr.includes('foo'));   //true
console.log(arr.includes(NaN));     //true

// 指数运算符 --------------------------------------------

console.log(Math.pow(2, 10));
// 补充的指数运算符 **
console.log(2 ** 10);